The use of digital image-forming apparatuses such as, for example, thermal ink-jet printers, large-format plotters, piezo-electric printers, laser printers, silver halide grade photo imaging apparatuses, and others has grown in recent years. The growth may be attributed to substantial improvements in print resolution and overall print quality coupled with appreciable reduction in cost, and ease of use. Today's image-forming apparatuses offer acceptable print quality for many commercial, business and household applications at costs lower than that offered in the past.
To illustrate advancement in the art that has evolved, there has been great interest in the area of reactive inks. These inks are designed such that a reaction occurs between two different inks at a border therebetween, e.g., an interaction such as precipitation occurs. This interaction can improve the edge acuity and/or color to color bleed between inks, and is typically particularly useful for plain paper applications. For example, in order to have good black to color bleed and halo control, many ink-jet ink sets have been designed so that contact between the black and color inks promote destabilization of the black color causing it to agglomerate on the page. This can be accomplished by adding materials to the color inks that cause precipitation of the black, usually acids or multivalent metal salts.
In general, a successful ink for color ink-jet printing often has the following properties: good crusting resistance, good stability, appropriate viscosity and surface tension, rapid dry time, low color-to-black bleed on plain and other papers, and/or consumer-safety. When placed into a thermal ink-jet system, the ink set should also be kogation-resistant.
Accordingly, it would be desirable to provide inks for use in ink-jet printing, which when used individually as well as in combination with other inks, have acceptable print quality, reliability performance, and/or environmental robustness.